Knitting machine and method

ABSTRACT

A FLAT V-BED KNITTING MACHINE HAVING AT LEAST TWO OPPOSED ARRAYS OF LATCH NEEDLES ARRANGED IN NEEDLE BEDS AND MEANS FOR ACTUATING NEEDLES OF THE ARRAYS INDEPENDENTLY IN SUCCESSION ALONG THE ARRAYS, IS CHARACTERISED BY TWO HOLD-DOWN ELEMENTS CARRIED ON THE SAME MEMBER WHICH IS SO MOUNTED THAT IT CAN BE MOVED TO BRING THE TWO HOLD-DOWN ELEMENTS ALTERNATELY INTO AN OPERATIVE POSITION IN WHICH THE OPERATIVE ELEMENT EXTENDS BENEATH ACTIVE NEEDLES OF THE ARRAYS, THE SAID MEMBER BEING ARRANGED TO CARRY THE HOLD-DOWN ELEMENTS ALONG THE ARRAYS OF NEEDLES IN SYNCHRONISM WITH THE ACTUATION OF THE NEEDLES AND THE OPERATIVE HOLD-DOWN ELEMENT BEING ARRANGED TO HOLD DOWN THE KNITTING SO THAT THE OPENED LATCHES MOVEUP THROUGH THE LOOPS ON THE NEEDLES AS THE NEEDLES RISE DURING KNITTING AND ARE CLOSED BY THE LOOPS AS THE NEEDLES DESCEND.

Oct. 19,

Filed Nov"; vl," 19s9 I nan-104T- 3,613,401

KNITTING mcnm. AND umaon' I j 1 Sheets-Sheet 1 [MENTOR BY KEITH JEFFCOAT AND MAX WILLIAM BETTS Davis, Roxie. Fait zhfull & Hapgood ATTORNEY Oct. 19 1971 JEFF'CWQAYT ETAL 3,613,401

- I KNITTING MACHINE AND mmxon Filed Nov; 7, 1969 @Sheets-Sheet 2 IN VE N TOR BY KEITH J EFFCOA' 1D 7 MAX WIL AM 8'" S Davis, Hoxie, Faithfull & Hapgood TTORNEY Oct. 19 1971 JEFi-CQAT ETAL 3,613,401

KNITTING MACHINE ANDJIETHOD Filed Nox r. v. 1969 4 Sheets-Sheet J INI/E N TOR BYKEITH JEFFCOAT AND MAX WILLIAM BETTS Davis, Hoxie, Faithful]. & Hapgood ATTORNE Y Oct. 19, 1971 .K. JEFFCOAT ETAL 3,613,401

KNITTING MACHINE AND METHOD Filed Nov. 7, 1969 4 Sheets-Sheet 4 IN VE/V TOR BY KEITH JEFFCOAT .AND

MAX WILLIAM BETTS Davis Hoxie, Faithfull & Hapgood ATTORNEY United States Patent 3,613,401 KNITTING MACHINE AND METHOD Keith Jctfcoat, Nuneaton, and Max William Betts, Coventry, England, assignors to Courtaulds Limited, London, England Filed Nov. 7, 1969, Ser. No. 874,938 Claims priority, application Great Britain, Nov. 8, 1968, 52,942/ 68 Int. Cl. D04b 7/00 US. C]. 66-60 13 Claims ABSTRACT OF THE DISCLOSURE A flat V-bed knitting machine having at least two opposed arrays of latch needles arranged in needle beds and means for actuating needles of the arrays independently in succession along the arrays, is characterised by two hold-down elements carried on the same member which is so mounted that it can be moved to bring the two hold-down elements alternately into an operative position in which the operative element extends beneath active needles of the arrays, the said member being arranged to carry the hold-down elements along the arrays of needles in synchronism with the actuation of the needles and the operative hold-down element being arranged to hold down the knitting so that the opened latches move up through the loops on the needles as the needles rise during knitting and are closed by the loops as the needles descend.

The present invention relates to a knitting machine with at least two co-operating arrays of latch needles and having provision for independent actuation of successive needles in the arrays. The invention is concerned with the provision in such a machine ofi an element to co-operate in the knitting action in such a way as to hold the loops on the needles down below the latches as the needles rise and cause the loops to engage under the latches and close them and then pass over the latches as the needles descend.

A machine having an element as just mentioned may be used with or without a conventional take-down mechanism but a machine used without a take-down mechanism avoids the disadvantages which stem from the uneven pull sometimes exerted by such a mechanism. In addition, the presence of an element as mentioned above can, in some circumstances, allow knitting to be started on a machine merely by supplying yarn to the empty needles. Prior to the present invention, it has sometimes been found necessary to place already knitted fabric on the needles of a machine when starting up so that the fabric can be gripped by the take-down mechanism in order to allow knitting to be carried on. Alternatively, a comb and weights have sometimes been used to apply tension to the first knitted loops. Use of such special means for starting up is normally unnecessary with the present element.

A knitting machine according to the invention is a flat V-bed knitting machine having at least two opposed arrays of latch needles arranged in needle beds and means for actuating needles of the arrays independently in succession along the arrays, the machine including two hold-down elements carried on the same member which is so mounted that it can be moved to bring the two holddown elements alternately into an operative position in which the operative element extends beneath active needles of the arrays, the said member being arranged to carry the hold-down elements along the arrays of needles in synchronism with the actuation of the needles and the operative hold-down element being arranged to hold down ice the knitting so that the opened latches move up through the loops on the needles as the needles rise during knitting and are closed by the loops as the needles descend.

The invention includes fabric or articles knitted on the machine just described.

References in the present specification to positions below the latches and to rising of the needles are given in adoption of the convention that the needles move up to take yarn and move down to draw a loop and that a position below the latch is further from the hook of the needles than the latch. Such references do not necessarily indicate any particular attitude, in relation to the vertical, of the needles or the machines in which they are incorporated.

The hold-down element may be constituted by a flat metal strip carried on a part of the said member which can flex in the transverse direction of the needle arrays. The member may be mounted on the cam box of the machine or a part associated therewith. The strip will be so mounted that it extends in a direction along the arrays of needles below the planes ofi the active raised needles.

The strip is preferably made of resilient material and may be shaped so that it has a part inclined to and merging smoothly with the part of the element which contacts the knitted loops, the inclined part being at the leading end of the element, that is the end which, in use, is adjacent to needles at the earliest part of the knitting cycle or which have not yet entered the knitting cycle.

The part of the strip which, in use, contacts the knitted loops may be arranged so that, when there is no yarn in the machine, this part slopes from its leading to its trailing portion in the downward direction with respect to the needle movement. This part of the element is arranged to adopt, in use, an attitude such that it extends in a direction parallel to a line joining the hooks of needles in the inactive position.

For knitting rib' fabric on two opposed arrays of needles in a V-bed knitting machine, a hold-down element in the form oil a round rod can be used with advantage and the trailing end of the rod may be narrowed so that loops drawn over the end of the rod will not be excessively large. The tip of the narrowed trailing end of such a rod may be located to the rear of the point at which the stitch cam has passed by the needles. For knitting tubular pieces of fabric on V-bed machines, the tip of the trailing end of the hold-down element is preferably located in advance of the point where the stitch cam relinquishes control over the knitting, advantageously in advance of the point where the final drawing ofi the loops begins.

The terms to the rear of and in advance and the terms leading and trailing end are used in this specification in relation to the progression of the knitting action through successive needles of the arrays.

A flat V-bed knitting machine may have more than one cam system mounted on the same carriage or on ditferent carriages and in such a machine two hold-down elements may be provided for each pair of knitting cam systems,

a separate one of the elements being arranged to cooperate in the knitting process on successive traverses of the cam system and their carriage. Each hold-down element preferably has a leading end shaped so as not to foul the fabric and the change over which removes one element of a pair from the operative position and brings the other element into the operative position is made at the end of each traverse of the cam system and carriage. A flat V-bed knitting machine may have needles mounted in more than two beds. For example, such a machine may have needles mounted in auxiliary beds movable longitudinally of the main beds. The present hold-down elements can be used in such machines.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a diagram showing two forms of hold-down element for machines according to the invention and the positions of these elements in relation to a cam track with which they may be associated,

FIG. 2 is a cross-section through the needle beds of a Hat V-bed knitting machine according to the invention having a hold-down element constituted by a rod,

FIG. 3 is a cross-section through the needle beds of a flat V-bed knitting machine according to the invention having a hold-down element constituted by a flat bar,

FIG. 4 is a side view of a mounting for a pair of holddown elements in a flat V-bed knitting machine according to the invention,

FIG. 5 is a perspective view of the mounting of FIG. 4 with some parts cut away,

FIG. 6 is a cross-section through part of the mounting of FIG. 4, and

FIG. 7 is a section on the line A-A of FIG. 5.

-FIG. 1 of the drawings shows two forms of resilient hold-down elements, designated by the numerals 10 and 11, respectively, which are suitable for use on a flat V-bed knitting machine. FIGS. 2 and 3 show the element 10 and the element 11, respectively. The means for mounting the hold-down elements on the machines are not shown in FIGS. 1, 2 and 3. Like reference numerals are used for like parts throughout the figures.

Each of the hold-down elements is shaped to extend in the direction along the array of needles in a position below the plane of the active, raised needles of each bed and below the uppermost level 13 of the position of closest approach of the beds and knock-over bits. Each holddown element comprises a leading end indicated at 17 and a trailing end indicated at 18. At the leading end of each of the elements 10 and 11 of FIG. 1 is a part 19 by which the element is secured to a mounting (not shown), and a part 20 which slopes, in use, towards the knitted fabric from the leading end to the trailing end of the element and merges smoothly into a part 21 which, in use, presses on the knitted loops and extends in a direction parallel to a line joining the hooks of needles in the rest position. However, the elements are so shaped that, when there is no yarn in the machine, the part 19 slopes from its leading end to its trailing end in the downward direction with respect to the needle movement. The shape of the hold-down elements is such as to achieve an approximately equal pressure on the knitted loops along the whole length of the element.

FIGS. 2 and 3 indicate the positions of the parts 21 of the two hold-down elements of FIG. 1 when the elements are in use. The loops of yarn and the knitted fabric have been omitted from these figures. The parts 21 are located between the needle beds 15 and 16, below the level of the tops of the knockover bits 13 and below the paths followed by the needles 14 in their upward movements.

The broken lines 13' in FIG. 3 indicate the planes of the faces of the closest portions of the needle beds 15 and 16 and knocking-over bits 13 in a machine in which these portions have faces which are parallel or substantially parallel to one another. The full lines in this figure indicate the faces of the closest portions of needle beds and knocking over bits having a normal configuration.

Means are provided on a fiat V-bed knitting machine according to the invention to move a hold-down element as shown in FIG. 1 along the two arrays of needles together with the carriage carrying the cam boxes of the machine. Thus relative motions of the hold-down element and the arrays of needles is brought about in synchronism with the actuation of the needles. The element may be mounted on the same carriage as the cam boxes, and there are two hold-down elements associated with each cam system in the machine, one for use in each direction of traverse of the carriage.

FIG. 1 shows the positions of the hold-down elements in relation to the knitting cycle of the needles of one array. If the machine is knitting rib fabric, the needles of the other array will be displaced one half a needle pitch with respect to those associated with the cam system shown in FIG. 1. 1f plain fabric is being knitted on the machine in the form of a tube, needles of only one array will be actuated during each traverse of the machine by the cam boxes. A cam track 22 is shown in FIG. 1 formed in a cam block 23 of the machine and the butts 24 of needles are shown located in the cam track. The line 25 shows the level of the upper edges of the butts of those needles which have had their hooks raised to the level of the front of the knocking over bits of the machine.

The parts 19 of both elements are located in advance of the needles taking part in the knitting action, and the portions 20 merge into the parts 21 on a line 26 in advance of a line 27 at which the needles are beginning to raise. The needles are beginning to draw a loop at the line 28 and at the line 29 are being released from the cam track 22 to find their own level.

The element 11 in the form of a flat bar terminates at a line 32 in advance of the line 28 where the needles are beginning to draw loops. The loops are thus not drawn over the bar and are of the usual length. The element 11 is particularly suitable for knitting articles in the form of tubes using both beds of a V-bed machine or for knitting on one bed only of a V-bed machine. It is preferably made as thin as possible whilst retaining sufiicient strength to exert the desired pressure on the knitted loops. The width of the element 11 is made equal to the distance between the beds of the machine at the level at which the element is located less a clearance between each side edge of the element and the associated bed for the knitted loops to pass through.

The element 10 in the form of a rod of circular section terminates at a line 36 to the rear of the line 29 where the cam track 22 relinquishes control of the needles. However, a portion 37 of the trailing end of the element, from the line 32 in advance of the line 28, where the needles begin to draw loops, to the rearmost point of the element, is of smaller cross-section than the main body of the part 21 of the element. The portion 37 is made as thin as possible whilst retaining sufl'icient strength to exert the desired pressure on the knitted loops. The part 21 of the element 10 has a diameter equal to approximately one half of the distance between the two beds at their closest point and is particularly suitable for knitting rib-type fabric.

The action of the hold-down elements described above is to press down on the knitted loops in the region where new loops are being knitted as the cam box moves along the array of needles, to operate successive needles independently. The hold-down element will be located at such a distance below the knock-over bits as is found to produce the best knitting and this position may be ditferent for different types and thicknesses of yarn and for different types of knitted fabric, The best position for a rod-shaped hold-down element will be different from the best position for a hold-down element with a flat cross-section.

A rodshaped element intended for use in producing rib knitting must press down on the yarn crossing between the beds at the level of the bases of the knock-over bits. Such an element will thus normally have its part 21 located at or just below the level of the tops of the needle beds.

A flat element intended for knitting tubular fabric will not normally be used for knitting a fabric construction in which yarns cross between the beds for a large number of consecutive courses and such an element will therefore press down on the knitted fabric by frictional contact with the knitted loops located between its side edges and the beds. In many circumstances, an advantageous position for the part 21 of such an element will be at a level between the loops which were last knocked-over and the row of loops immediately preceding these.

Such a hold-down element can be used when knitting on the needles of one of the arrays.

A flat hold-down element such as the element 11 can, however, be used to knit some courses of rib knitting and, when starting up knitting with empty needles in a machine having such a hold-down element, it is advantageous to knit at least one course of rib before commencing tubular knitting.

In a fiat V-bed knitting machine having a hold-down element such as those described above, an end of the holddown element shaped to avoid snaring the knitted loops must always be presented to the knitting as the leading end of the element. In FIGS. 4 to 7 is shown a machine according to the invention in which this is achieved by mounting two hold-down elements on the same support member in such a way that only one element is in an operative position during each traverse of the cam carriage and the operative element presents a suitably shaped end to the knitting as its leading end.

A mounting for the hold-down elements in a V-bed knitting machine according to the invention is shown in FIGS. 4, 5, 6 and 7. The mounting comprises two side plates and 41 secured to bridges 42 and 43 extending between the two cam boxes of the machine (not shown) and thus across and above the needle beds. A slider 44 is mounted for sliding movement between the plates and is guided by bosses, one of which is shown by reference numeral 45 (FIG. 6) secured to the slider and engaged in a keyway 46 in the side plate 40.

The slider 44 is in the form of a rack having teeth 47 in mesh with a gear wheel 48 (having 40 teeth) rotatably mounted in the side plates 40 and 41. The wheel 48 is formed in one piece with a gearwheel 49 having 20 teeth and in mesh with the teeth 50 constituting a rack on a further slider 51. The slider 51 is mounted for sliding movement longitudinally of the plates 40 and 41 and guided by bosses 54 secured to the slider and engaged in a keyway 55 in a cover plate 56 secured to the side plate 41. The side plate 41'overlaps the keyway 55 and serves to hold the bosses 54 in the keyway.

Projecting from one side of the slider 51 at the lower edge thereof (FIG. 7) are two pins 57 and 58 which cooperate with the upper V-shaped ends of downwardly projecting arms 59 and 60 which constitute supporting members for pairs of hold-down elements 61, 62 and 63, 64. The arms 59 and 60 are pivoted at 67 and 68, respectively, between depending plates 69 and 70 between which are located abutments 73, 74 and 75, 76 which limit the pivoting movements of the arms.

The lower portions of the arms 59 and 60 are constituted by thin flexible strips 77 and 78 of a berylliumcopper alloy to which the hold-down elements are secured. Each pair of hold-down elements 61, 62 and 63, 64 is formed to a single strip of metal of rectangular cross-section. In FIG. 4 the hold-down elements 61 and 63 are in operative positions for movement to the right in the figure and a leading portion 61', 63' of each element is inclined downwardly and rearwardly towards the needle beds, a trailing portion 61", 63" of each holddown element being more nearly parallel to the longitudinal direction of the beds.

The arms 59 and 60 of the mounting of FIG. 4 are arranged to be rotated on their pivots 67 and 68 at the end of each traverse of the cam carriage of the machine in order to bring the previously inoperative hold-down elements to the operative position. 7,:

This is achieved as follows. The slider 44 is formed at its ends with upwardly projecting abutments 81 and 82. At the end of the traverse of the cam carriage and mounting to the right in FIG. 5, the abutment 82 will come into contact with a stop 83 constituted by the end face of an arm 84 which extends inwardly parallel to and over the needle beds. The stop 83 arrests the slider 44 while the cam carriage and the remainder of the mounting continue to move to the right to complete the traverse. During this movement, the slider moves to the left relative to the plates 40 and 41 causing the gear wheel 48 to rotate in the anti-clockwise direction in FIG. 4. Gearwheel 49 rotates in the same direction and causes the slide 51 to move to the right relative to the plates 40 and 41. The result of this movement of the slider 51 is that the pin 57 impinges upon the lug 87 at the top of the arm 59 and brings about clockwise rotation of the arm in FIGS. 4 and 5. The pin 58, which is initially located a greater distance from the lug 88 at the top of the arm 60 than the distance of the pin 57 from the lug 87, brings about clockwise rotation of the arm 60 which commences later than the clockwise rotation of the arm 59. The arms 59 and 60 continue to rotate from the positions shown in full lines in FIG. 4 where they are located respectively by faces 91 and 92 of abutments 73 and 74 and by faces 93 and 94 of abutments and 76 to the positions shown in broken lines in FIG. 4 where they are located respectively by faces 95 and 96 of abutments 73 and 74 and by faces 97 and 98 of abutments 75 and 76. When the arms 59 and 60 are in their new positions, the hold-down elements 62 and 64 are in the operative positions for a traverse to the left in FIG. 4 and the hold-down elements 61 and 63 have been moved to inoperative positions.

At the end of the traverse to the left the abutment 81 of the slider 44 impinges on a stop (not shown) similar to the stop 83 and the leftwards movement of the slider 41 is thus arrested whilst the cam carriage and the mounting continue their leftwards movement to complete the traverse. By a similar action to that described above, the pins 57 and 58 now contact lugs 101 and 102 of the arms 59 and 60 and the arms are rotated back to the positions shown in full lines in FIG. 4 ready for the next traverse to the right. The rotation of the arms again takes place sequentially although at the end of a leftwards traverse, the arm 60 leads.

During the pivoting movement of the arms 59 and 60, as the upper ends of the arms rise, the pins 57 and 58 enter slots 103 and 104 respectively formed at the point of the V at the top of each arm. In their end positions, the arms are locked in place by the pins 57 and 58 as well as being located by the faces of the abutments 73 The hold-down elements in a machine according to the invention may be treated so that their coeificient of friction with respect to knitting yarns is low or alternatively they may be coated with a material having such a low coefiicient of friction. The element may be made of or coated with, a synthetic plastics material, for example, polytetrafluoroethylene.

The hold-down elements may be in the form of brushes. In some cases they may also be flexible elongated elements; for example flexible metalwires having sleeves of polytetrafluoroethylene.

Some of the hold-down elements described above can be used in conjunction with a further hold-down member illustrated in broken line in conjunction with the holddown element 11 in FIG. 1. The further member may be constituted by a wheel or by a foot shaped as shown and may be spring loaded so that it is urged downwardly in FIG. 1.

Advantageously, the member 80 is arranged so that during knitting it extends down in relation to the element 11 approximately to the position shown in FIG. 1 and is located, in relation to the associated cam system, in the position shown in FIG. 1. The function of the member 80 is to hold down the loops knitted during the immediately preceding passage of the hold-down element 11, resisting the tendency of the fabric to be pulled up in relation to the beds with consequent shortening of the knitted loops.

What is claimed is:

1. In a flat V-bed knitting machine having at least two opposed arrays of latch needles arranged for individual 7 upward and downward movement in needle beds, and cam means traversing the needle beds alternately in opposite directions to activate the needles independently in succession along the arrays, the improvement which comp a carrier connected to and traversable with said cam means;

a supporting member pivotably mounted on said carrier and extending downwardly along a plane positioned between the needle beds;

two hold-down elements mounted on said supporting member at its lower end, projecting in opposite directions away from said lower end of said supporting member and arranged for movement between the needle beds for holding down fabric being knitted, thereby facilitating the upward movement of needles having opened latches through yarn loops and closure of the latches by the yarn loops during downward needle movement;

means acting on said supporting member above its pivot for pivoting said supporting member to bring said hold-down elements alternately into an operative position beneath the activated needles of the arrays on successive alternate traverses of the arrays by said cam means; and

means for locking the supporting member against pivotal movement during the traverse movement of said cam means to maintain the orientation of said hold-down elements relative to the needle beds.

2. A machine as claimed in claim 1, wherein said supporting member includes a lower portion capable of flexing transverse to the needle arrays.

3. A machine as claimed in claim 2, wherein said lower portion is constituted by a flexible metal strip.

4. A machine as claimed in claim 3, wherein the flexible metal strip is made of an alloy of beryllium and copper.

5. A machine as claimed in claim 1, wherein each of said hold-down elements has a leading end which in the operative position is inclined downwardly and rearwardly and which merges smoothly with a trailing end of said hold-down element which is more nearly parallel to the longitudinal direction of the needle beds.

6. A machine as claimed in claim 1 having movable knock-over bits associated with the needle beds, wherein said hold-down elements are formed from a metal strip arranged for positioning longitudinally along the needle beds below the uppermost level of the closest approach of the knock-over bits.

7. A machine as claimed in claim 1, wherein said pivoting means includes a slider mounted on said carrier for pivoting said supporting member at the end of each 8 traverse of the needle beds by the cam means to bring the previously inoperative hold-down element into an operative position for the next traverse of the needle beds by the cam means.

8. A machine as claimed in claim 7, wherein said slider includes a rack, a gearwheel mounted on said carrier for transmitting motion from said slider rack to a second rack, said second rack movably mounted on said carrier and mechanically coupled to said supporting member for providing pivotal movement thereto.

9. A machine as claimed in claim 8, including a plurality of supporting members pivotally mounted on said carrier, each of said supporting members having two hold-down elements connected thereto, said second rack being mechanically coupled to said supporting members to cause pivotal movement thereof, so that one of said hold-down elements of each of said supporting members is operative during each traverse of the cam means.

10. A knitting machine as claimed in claim 1, including movable knock-over bits associated with said needle beds and having faces which are substantially parallel at their closest approach, each of said hold-down elements arranged for positioning between said parallel faces when in the operative position.

11. A knitting machine as claimed in claim 10, including means for holding down the loops knitted during the proceding passage of said hold-down elements to resist any tendency of the fabric to be pulled upward in relation to the needle beds with resultant shortening of the knitted loops.

12. A knitting machine as claimed in claim 11, wherein said holding down means is a wheel mounted on said carrier for downward movement toward the needle beds.

13. A knitting machine as claimed in claim 1, wherein each hold-down element is constituted by a round rod having a trailing portion which is narrower than the leading portion of the rod.

References Cited UNITED STATES PATENTS 3,049,900 8/1962 Bram 6660 718,951 1/1903 Nichols.

FOREIGN PATENTS 903,825 8/1962 Great Britain 6660 908,402 10/1962 Great Britain 66-60 377,034 6/1964 Switzerland 6660 382,361 11/1964 Switzerland 6664 RONALD FELDBAUM, Primary Examiner 

